OLED display devices, with advantages such as low energy consumption, high luminance, short response time, wide viewing angle, and light weight, have been broadly used in devices such as mobile communication terminals, personal digital assistants (PDAs) and tablet computers. OLED display devices are classified into the passive matrix type and active matrix type. The active matrix type OLED display devices utilize thin film transistors (TETs) to drive OLEDs.
A white organic light emitting diode (WOLED) device provides high resolution and large scale displays, and can be used in a backlight of a liquid crystal display (LCD) device or a full color display device employing color filters. White OLED and other top-emitting display devices have relatively high aperture ratios, but the light output and viewing angles of these display devices are not ideal. To output colored light, a color filter substrate is used to filter white light generated by the OLED layer. The color filter substrate includes color filters and a black matrix formed on a glass substrate of the display panel. When the emitted light enters the glass substrate, the black matrix structure would absorb part of the light to reduce the reflection and improve the contrast ratio of the OLED display.
However, a conventional black matrix absorbs light, including the diffused light generated by many pixels, which may reduce the brightness levels of the display panels. Further, conventional black matrix is often made of heavy metals, such as chromium. Such materials pollute the environment. In addition, the processes implemented to clean up manufacturing wastes containing heavy metals are often burdensome and costly.
It is therefore desirable to improve the designs of OLED/LC structures to reduce pollution in the manufacturing processes, and to improve contrast ratios and view angles of the display panels.